H8SX1663 datasheet(331/1158 Pages) RENESAS

tên linh kiện	H8SX1663

Giải thích chi tiết về linh kiện	Renesas 32-Bit CISC Microcomputer H8SX Family / H8SX/1600 Series

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Section 6 Bus Controller (BSC)

Rev.1.00 Jun. 07, 2006 Page 279 of 1102

REJ09B0294-0100

(2) Self-Refresh Mode

Some SDRAMs have a self-refresh mode (battery backup mode). The self-refresh mode is a kind

of standby mode and refresh timing and refresh address are controlled internally.

The self-refresh mode is selected by setting the RFSHE and SLFRF bits in REFCR to 1. The

SELF command is issued as shown in figure 6.79 by executing the SLEEP instruction to enter the

self-refresh mode.

When an auto-refresh is requested on a transition to the standby mode, the auto-refresh is first

performed and then the self-refresh mode is entered.

When making a transition to the self-refresh mode, set the OEE bit in SBYCR to 1 and connect the

CKE pin.

When the self-refresh mode is used, do not clear the OPE bit in SBYCR to 0.

Precharge-sel

RAS

CAS

CKE

PALL

SELF

NOP

Software standby

RD/

Address bus

High

Figure 6.79 Self-Refresh Timing

(TPC1 = 0, TPC0 = 0, RCW1 = 0, RCW0 = 0, RLW1 = 0, RLW0 = 0)

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